Evaporator apparatus



March 1956 w. M. BYERLEY EVAPORATOR APPARATUS Filed Aug. 25, 1951 NOE INVENTOR Wilbur M Byerley ATTORNEY 2,739,57 EVAPORATGR APPARATUS Wilbur M. Byeriey, Crum lLynne, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pin, a corporation of Pennsylvania Application August 23, 1951, Serial No. 243,263 2 Claims. (Cl. 122-34) This invention relates to evaporators and has for an object the provision of evaporator apparatus equipped with water separator means having provision for imparting superheat to the vapor generated in the evaporator apparatus.

It has been proposed to install a separate superheater tube section in an evaporator to effect superheating of the vapor in order to ensure that the vapor will reach the consuming apparatus in a dry condition. Because of the possibility that water might splash on such a tube section, causing rapid formation of scale thereon, an arrangement which employs the superheating section inside the evaporator shell is considered undesirable.

It is another object of the invention to provide an improved evaporator apparatus having a combination water separator and superheater section mounted in an upper wall of the evaporator to prevent the splashing of water on dry tube surfaces and resultant scaling of the tubes.

in order that the separator can operate most efliciently in conjunction with a superheating section, it is desirable to locate the superheating section in the vapor flow path downstream of or after the separator.

A further object of the invention is the provision of means for utilizing superheated steam which is supplied to the tube bundle of an evaporator for imparting a small amount of superheat to the vapor generated in the evaporator, following passage of such vapor through a water separator.

A further object of the invention is to provide an improved evaporator apparatus including a tube bundle adapted to be supplied with superheated steam for generating vapor which is discharged by way of a water separator, together with auxiliary superheater means associated with the separator and with the source of superheated steam in such a manner as to eifect superheating of the vapor following removal of water therefrom and de-superheating of the steam before it enters the tube bundle, thereby minimizing formation of scale on the tube bundle.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a sectional elevation of a heat exchange apparatus or evaporator having a combination water separator and superheater section constructed in accordance with the invention;

Fig. 2 is an enlarged detail, sectional view of the superheater section shown in Fig. l; and

Fig. 3 is a sectional view taken substantially along the line IIIIII of Fig. 2.

Referring to Fig. 1 of the drawing, the heat exchange apparatus therein illustrated constitutes an evaporator having a cylindrical shell 11 in which is formed a vapor chamber 12, which is closed at one end by a wall 13 and at the opposite end by a removable cover 14. Mounted in the lower portion of the shell 11 is a tube bundle 15 having an inlet header 16 and an outlet header 17, which States Patent 2,739,575 "Patented Mar. 27, 1956 communicates by way of a discharge pipe 19 with an outlet pipe 20. A water supply conduit system 21 having discharge nozzles 22 is mounted in the shell 11 above the tube bundle 15. It will be understood that the tube bundle 15 is adapted for circulation therethrough of a heating fluid, such as steam, for effecting evaporation of water supplied to the vapor chamber 12 by way of the conduit system 21. Resultant vapors aredischarged from the apparatus by way of a water separator 25 of suitable construction, such for example, as that disclosed in Patent No. 2,344,898, issued to J. P. Rathbun, March 21, 1944, and assigned to the assignee of the present invention. A suitable source of superheated steam (not shown) may be associated with the evaporator 10 for supplying superheated steam to the inlet header 16 by way of a conduit including joined sections 26, 27, 28 and 29.

According to the invention, the separator 25 is provided with an extension comprising a cylindrical superheater casing section 39 having a superheater chamber 31, the lower end of which is closed by a tube sheet 32 and the upper end of which is closed by a tube sheet 33. The lower end of the cylindrical casing section 30 may be welded or other wise suitably secured to the outer casing of the separator 25. The upper or outlet end of the superheater casing section 31) may be bolted or otherwise suitably secured to a conduit 34, which leads to the usual consumer apparatus (not shown). Formed in the upper portion of the casing section 30 is an opening 37 into which the steam conduit section 26 is secured for supplying superheated steam to the superheater chamber 31. An outlet opening 38 is formed in the lower portion of the superheater casing section 30 for receiving an end of the section 27 of the superheated steam conduit assembly. Formed in the casing section 30 intermediate the conduit sections 26 and 27 is an annular corrugation or expansion portion 40. A plurality of spaced parallel vapor conducting tubes 41 are disposed in the superheater chamber 31, the lower ends of the tubes being secured in the tube sheet 32 in communication with the chamber 12 of the evaporator, and the uppermost ends of the tubes being secured in the baflie 33 for communication with the conduit 34.

From the foregoing, it will readily be understood that with the water separator 25 provided with the superheater comprising casing section 30 and tubes 41, vapor generated in the vaporizing chamber 12 of the evaporator will pass through the separator 25 and thence through the tubes 41 to the discharge conduit 34, while superheated steam entering by way of the conduit section 26 will be circulated through the superheater chamber 31 prior to flow of such steam through conduit sections 27, 28 and 29 to the tube bundle 15. Any water droplets leaving the evaporating chamber 12 with the vapor generated therein will thus be removed during passage of the vapor through the separator 25, and the desired amount of superheat will then be added to the relatively dry vapor during flow through the tubes 41. At the same time, due to the transfer of heat from the superheated steam in the chamber 31 to the vapor going through the tubes 41, the steam entering the tube bundle 15 of the evaporator will be sufficiently tie-superheated to hold down excessive scaling of the inlet ends of the tubes of which'the tube bundle 15 is composed.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. Evaporator apparatus comprising a shell for receiving water to be evaporated, steam heat exchange means disposed in the lower portion of said shell, water 3 spraying means disposed intermediate the top of said shell and said heat exchange means, separator means for removing entrained moisture from vapor generated in said shell, superheating means for imparting superheat to the vapor discharged from said separator means, said superheating means including a casing provided with a steam inlet and a steam outlet and further provided With superheat exchange means, and a steam conduit providing a communication between said steam outlet and said heat exchange means, said superheating means being disposed externally of said shell and being supported by said shell, said separator being disposed intermediate and in communication with said shell and said superheat exchange means, whereby said separator acts as a barrier preventing moisture from being conveyed to said super- 15 heat exchange means.

2. The structure recited in claim 1 in which the casing of the superheating means comprises an outer tubular wall forming a steam chamber, said wall including an annular expansion portion.

References Cited in the file of this patent UNITED STATES PATENTS Kerr Feb. 27, 1934 Badenhausen Dec. 14, 1943 FOREIGN PATENTS 

1. EVAPORATOR APPARATUS COMPRISING A SHELL FOR RECEIVING WATER TO BE EVAPORATED, STEAM HEAT EXCHANGE MEANS DISPOSED IN THE LOWER PORTION OF SAID SHELL, WATER SPRAYING MEANS DISPOSED INTERMEDIATE THE TOP OF SAID SHELL AND SAID HEAT EXCHANGE MEANS, SEPARATOR MEANS FOR REMOVING ENTRAINED MOISTURE FROM VAPOR GENERATED IN SAID SHELL, SUPERHEATING MEANS FOR IMPARTING SUPERHEAT TO THE VAPOR DISCHARGED FROM SAID SEPARATOR MEANS, SAID SUPERHEATING MEANS INCLUDING A CASING PROVIDED WITH A STEAM INLET AND A STEAM OUTLET AND FURTHER PROVIDED WITH SUPERHEAT EXCHANGE MEANS, AND A STEAM CONDUIT PROVIDING A COMMUNICATION BETWEEN SAID STEAM OUTLET AND SAID HEAT EXCHANGE MEANS, SAID SUPERHEATING MEANS BEING DISPOSED EXTERNALLY OF SAID SHELL AND BEING SUPPORTED BY SAID SHELL, SAID SEPARATOR BEING DISPOSED INTERMEDIATE AND IN COMMUNICATION WITH SAID SHELL AND SAID SUPERHEAT EXCHANGE MEANS, WHEREBY SAID SEPARATOR ACTS AS A BARRIER PREVENTING MOISTURE FROM BEING CONVEYED TO SAID SUPERHEAT EXCHANGE MEANS. 